Internal Server Error

Hope your all keeping well. I just have a quick question.

My website was working perfectly but today I went on to view the blog and was greated by this….

https://www.jmaxphotography.com/?page_id=634

Do you know what may have caused this?

Also if I go onto the blog via the control panel I am able to view the pages within the blog directly. (as shown below)

https://www.jmaxphotography.com/?p=3009

Your help on this matter would be greatly appreciated.

Regards,
John